Monoclinic sulphur, obtained by crystallizing fused sulphur, melts at I 19.5°, and admits of undercooling even to ordinary temperatures, but contact with a fragment of the rhombic modification spontaneously brings about the transformation.

Lehmann it melts at 168° (or at a slightly lower temperature in its water of crystallization) and on cooling forms optically isotropic crystals; at 125.6° the mass becomes doubly refracting, and from a solution rhombohedral (optically uniaxial) crystals are deposited; by further cooling acicular rhombic crystals are produced at 82.8°, and at 32.4° other rhombic forms are obtained, identical with the product obtained by crystallizing at ordinary temperatures.

The mere retention of the same crystal form by homologous substances is not a sufficient reason for denying a morphotropic effect to the substituent group; for, in the case of certain substances crystallizing in the cubic system, although the crystal form remains unaltered, yet the structures vary.

PYRRHOTITE, a mineral species consisting of iron sulphide and crystallizing in the hexagonal system.

Though introduced with success from Santo Domingo about the middle of the T 8th century, the sugar industry practically dates from 1796, when Etienne Bore first succeeded in crystallizing and clarifying the syrup. Steam motive power was first introduced on the plantations in 1822.

This product melts at 86° C., and becomes anhydrous when heated to 110° C. The anhydrous compound can also be prepared, as hard crusts melting at 146°, by crystallizing concentrated aqueous solutions at 30 to 35°.

To the kettle, two-thirds full of crystals of lead, is now added lead of the same tenor in silver, the whole is liquefied, and the cooling, crystallizing, skimming and ladling are repeated.

The plant consists of two tilting oval metal pans (capacity 7 tons), one cylindrical crystallizing pot (capacity 22 tons), with two discharging spouts and one steam inlet opening, two lead moulds (capacity 31 tons), and a steam crane.

By dissolving red lead, Pb304, in glacial acetic acid and crystallizing the filtrate, colourless monoclinic prisms of lead tetracetate, Pb(C2H302)4, are obtained.

Besides its connexion with the speculations of Anselm, the doctrine of Roscellinus was also of decisive influence within the schools in crystallizing the opposite opinion.

Dissolves the most uncrystallizable in preference to that which is most crystallizable sugar," and the patentee speaks of " a discovery I have made that no solution, unless highly concentrated, of sugar in water can without material injury to its colouring-and crystallizing power, or to both, be exposed to its boiling temperature during the period required to evaporate such solution to the crystallizing point."

The gold chloride of commerce, which is used in photography, is really a hydrochloride, chlorauric or aurichloric acid, HAuC1 4.3H 2 O, and is obtained in long yellow needles by crystallizing the acid solution.

The potassium salt is obtained by crystallizing equivalent quantities of potassium and auric chlorides.

MARCASITE, a mineral with the same chemical composition as pyrites, being iron disulphide FeS2, but crystallizing in the orthorhombic instead of in the cubic system.

Calcium nitrate, Ca(N0,)2.4H20, is a highly deliquescent salt, crystallizing in monoclinic prisms, and occurring in various natural waters, as an efflorescence in limestone caverns, and in the neighbourhood of decaying nitrogenous organic matter.

When dissolved in water it yields some NaOH and H202; on crystallizing a cold 'solution Na202.8H20 separates as large tabular hexagonal crystals, which on drying over sulphuric acid give Na 2 0 2.2H 2 0; the former is also obtained by precipitating a mixture of caustic soda and hydrogen peroxide solutions with alcohol.

The acid sulphate, NaHSO 4, also known as bisulphate of soda, is obtained as large asymmetric prisms by crystallizing a solution of equivalent quantities of the normal sulphate and sulphuric acid above 50°.

The heptahydrate, Na2C03.7H20, is obtained by crystallizing a warm saturated solution in a vacuum; it appears to be dimorphous.

On crystallizing a solution, the hydrate KOH 2H 2 0 is deposited; 2KOH 9H 2 0 and 2KOH 5H 2 0 have also been obtained.

- Potassium fluoride, KF, is a very deliquescent salt, crystallizing in cubes and having a sharp saline taste, which is formed by neutralizing potassium carbonate or hydroxide with hydrofluoric acid and concentrating in platinum vessels.

Potassium sulphite, K 2 S0 3, is prepared by saturating a potash solution with sulphur dioxide, adding a second equivalent of potash, and crystallizing in a vacuum, when the salt separates as small deliquescent, hexagonal crystals.

The salt K2S03 H20 may be obtained by crystallizing the metabisulphite, K 2 S 2 0 5 (from sulphur dioxide and a hot saturated solution of the carbonate, or from sulphur dioxide and a mixture of milk of lime and potassium sulphate) with an equivalent amount of potash.

The salt K2S03 2H20 is obtained as oblique rhombic octahedra by crystallizing the solution over sulphuric acid.

Occasionally monoclinic crystals are obtained by crystallizing from a strong solution.

H 3 C CO NH 3 CO CH 3 H3C C - NH - C CH3 On nitration it yields chiefly meta-nitro-benzaldehyde, crystallizing in needles which melt at 58° C. The ortho-compound may be obtained by oxidizing ortho-nitrocinnamic acid with alkaline potassium permanganate in the presence of benzene; or from ortho - nitrobenzyl chloride by condensing it with aniline, oxidizing the product so obtained to ortho-nitrobenzylidine aniline, and then hydrolysing this compound with an acid (Farben fabrik d.

Till the last it was obliged to contend with the most formidable difficulties: yet it succeeded in effecting many notable reforms and in illuminating and crystallizing the distinctive doctrines of Catholicism.

Potassium aluminate, K 2 Al 2 0 4, is obtained in solution by dissolving aluminium hydrate in caustic potash; it is also obtained, as crystals containing three molecules of water, by fusing alumina with potash, exhausting with water, and crystallizing the solution in vacuo.

Taking up mathematics when not only his mind was already formed but his thoughts were crystallizing into a philosophical system, Hobbes had, in fact, never put himself to school and sought to work up gradually to the best knowledge of the time, but had been more anxious from the first to become himself an innovator with whatever insufficient means.

There is reason to suppose that the change described takes place in two stages, the gypsum first forming orthorhombic crystals and then crystallizing in the monosymmetric system.

Thallous fluoride, T1F, forms white glistening octahedra; it is obtained by crystallizing a solution of the carbonate in hydrofluoric acid.

Thallous nitrate, T1NO 31 is obtained as white, rhombic prisms by crystallizing a solution of the metal, oxide, carbonate, &c., in nitric acid.

This salt is obtained by roasting wolfram with sodium carbonate, lixiviating, neutralizing the boiling filtrate with hydrochloric acid and crystallizing at ordinary temperatures.

Of the phosphotungstic acids the most important is phosphoduodecitungstic acid, H 3 PW, 2040 nH 2 O, obtained in quadratic pyramids by crystallizing mixed solutions of orthophosphoric and metatungstic acids.

Hypophosphorous acid, HP(OH) 2, discovered by Dulong in 1816, and obtained crystalline by Thomson in 1874 (Ber., 7, P. 994), is prepared in the form of its barium salt by warming phosphorus with baryta water, removing the excess of baryta by carbon dioxide, and crystallizing the filtrate.

The second, P4S7, is obtained by heating a mixture of red phosphorus and sulphur in the proportions given by P4S7+5% P4S3, and crystallizing from carbon disulphide in which P 4 S 3 is readily soluble.

The most important of these is sulphate of ammonia, which is used for agricultural purposes as a manure, and is obtained by passing ammonia into sulphuric acid and crystallizing out the ammonium sulphate produced.

Ferrous bromide, FeBr2, is obtained as yellowish crystals by the union of bromine and iron at a dull red-heat, or as bluish-green rhombic tables of the composition FeBr26H2O by crystallizing a solution of iron in hydrobromic acid.

The iron alums are obtained by crystallizing solutions of equivalent quantities of ferric and an alkaline sulphate.

Ferrous nitrate, Fe(NO3)2.6H2O, is a very unstable salt, and is obtained by mixing solutions of ferrous sulphate and barium nitrate, filtering, and crystallizing in a vacuum over sulphuric acid.

Ferric nitrate, Fe(NO3) 3, is obtained by dissolving iron in nitric acid (the cold dilute acid leads to the formation of ferrous and ammonium nitrates) and crystallizing, when cubes of Fe(NO3)3.6H20 or monoclinic crystals of Fe(N03)3.9H20 are obtained.

ORPIMENT (auripigmentum), arsenic trisulphide, As2S3, or yellow realgar, occurring in small quantities as a mineral crystallizing in the rhombic system and of a brilliant goldenyellow colour in Bohemia, Peru, &c. For industrial purposes an artificial orpiment is manufactured by subliming one part of sulphur with two of arsenic trioxide.

Acenaphthalene, C12 H8, a hydrocarbon crystallizing in yellow tables and obtained by passing the vapour of acenaphthene over heated litharge.

The pentaiodide, AsI5, appears to be formed when a mixture of one part of arsenic and seven parts of iodine is heated to 190° C., but on dissolving the resulting product in carbon bisulphide and crystallizing from this solvent, only the tri-iodide is obtained.

Mannite is obtained by extracting manna with alcohol and crystallizing the solution.